title: Novel use of rituximab in a case of Riedel's thyroiditis refractory to glucocorticoids and tamoxifen.
abstract: A 42-year-old woman presented with a rapidly enlarging right-sided thyroid mass and underwent hemithyroidectomy. Riedel's thyroiditis was only diagnosed upon surgical decompression of the right carotid artery 2 years later. She became more symptomatic as Riedel's thyroiditis progressed, and mediastinal fibrosclerosis developed over the next 12 months. Oral prednisolone failed to improve her condition, and she was commenced on tamoxifen. Despite initial improvement, her symptoms recurred 2 years later, mainly arising from compression of the trachea and esophagus at the thoracic inlet. Fluorodeoxyglucose positron emission tomographic scan showed locally advanced active invasive fibrosclerosis in the neck and mediastinum. An elevated activin-A level of 218 pg/mL was consistent with active inflammation. IgG subtypes (including IgG4) were normal. Two courses of iv methylprednisolone were given but only produced transient improvement. Subsequently, the patient received 3 doses of i.v. rituximab at monthly intervals and had prompt sustained symptomatic improvement. Activin-A level decreased to 122 pg/mL 10 months after rituximab therapy. Fluorodeoxyglucose positron emission tomographic scan 6 weeks after therapy showed reduction in inflammation. A further scan at 10 months demonstrated ongoing response to rituximab. This is a case of refractory Riedel's thyroiditis with symptomatic, biochemical, and radiological improvement that has persisted 14 months after rituximab. The likelihood and duration of response to rituximab in Riedel's thyroiditis requires further study.
authors.affiliation: Department of Endocrinology and Diabetes, 5th Floor, Centre Block, The Alfred, Commercial Road, Melbourne 3004, Victoria, Australia.
authors.forename: Shui-Boon
authors.initials: SB
authors.lastname: Soh
authors.forename: Alan
authors.initials: A
authors.lastname: Pham
authors.forename: Robyn E
authors.initials: RE
authors.lastname: O'Hehir
authors.forename: Martin
authors.initials: M
authors.lastname: Cherk
authors.forename: Duncan J
authors.initials: DJ
authors.lastname: Topliss
mesh_terms: D000328:Adult; D058846:Antibodies, Monoclonal, Murine-Derived / Q000627:therapeutic use*; D019299:Decompression, Surgical; D005260:Female; D005938:Glucocorticoids / Q000627:therapeutic use; D006801:Humans; D011239:Prednisolone / Q000627:therapeutic use; D019233:Retreatment; D000069283:Rituximab; D013629:Tamoxifen / Q000627:therapeutic use; D013965:Thyroidectomy; D013966:Thyroiditis / Q000188:drug therapy* / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D005938:Glucocorticoids; D013629:Tamoxifen; D000069283:Rituximab; D011239:Prednisolone